Carburetor



Oct. 16, 1928.

M. PURvls ET AL CARBURETOR Filed June 29. 1926 CDH Patented @et 16,i928.

MATTHEW. PURVIS AND THOMAS LELE, l QF PLYMUTH, ENGLAND.

CARBURETOR.

Application led June 29, 1926, Serial flo. and in Great Britain May 25,1926.

rihis invention relates to carburetors for internal combustion enginesand has for its object to devise improvements in the construction andarrangement of carburetoi's which will obviate the necessity for anyfloat chamber and choke tubes, ywill render the carburetor simple andcheap to manufacture and easy to'manipulate and control, will facilitatethe cleaning of the saine when necessary and will Vlead to anv increasein power obtainable for aA given consumption of fuel, J l

The invention consists in a carburetor for internal combustion enginescomprising a :iet tube having` a yplurality of lateral open ings or aslot therein and passing across the air inlet pipe and a movable pistonsurrounding the jet tube and controlling both the air and liquid fuelsupplies simultaneously.

rlhe invention also consists in other details and arrangementsherinafterdescribed or indicated.

The accompanying drawings illustrate two modes of carrying out theinvention.

Figure l is a sectional elevation of one convenient form of carburetorconstructed in accordance with the invention.`

j Figure 2 is a section on the line 2--2 of Figure l. y A

Figure 3 is a plan of Figure l but showing the piston moved into aposition in which the air inlet and fuel jet openings are par tia lyopen.

Figure 4 is a sectional view showing a modification of a detail.

ln carrying our invention into eiect in one convenient manner asillustrated in Figures l to 3, we form our improved carburetor with acylinder a, piston and jet tube c, the whole being' united with the airinlet tube d and being provided with flanges e so that it may be mountedconveniently upon the top of the induction manifold, it beingunderstood, however, that the carburetor may be fitted in any othersuitable position and by any other suitable means.

The jet tube c is connected with the inlet f for the liquid fuel supplyand passes across the air inlet tube d and in the form illustrated isprovided with a plurality of down-V wardly directed openings orapertures y, this direction of the openings'being chosen'in the formillustrated which is adapted to be mounted upon the top of the inductionmanitine spray giving perfect acceleration while at the Asaine timeovercoming the diiiicultyr experienced when starting cold sincev nopriming will be necessary.

, iiny other suitable arrangement of the apertures may be chosen,however, depending upon the location of the carburetor, and,

moreover, it will be understood that in place oi' such apertures we mayadopt one or more longitudinal slots in the wall of the jet to replacethe apertures or sets of apertures (when more than one set is employed).

The piston o is adapted to surround thejet tube in a fluid-tightmannerand is con- 'trollable by any suitable Bowden wire or other actua-tinggear connected with the shank or extension 71, of the piston, thearrangement being such that when the piston is moved towards the rightlooking at Figure l the air inlet and the fuel jets will be graduallyopened to an extent determined by the extent of movement of the pistonso that thereby the air and fuel supplies will be simultaneouslycontrolled and the proper mixture ratio maintained under all condi tionsof working.

` Moreover since the piston surrounds the jet tube in a i'iuidtightmanner and cont pletely closes the fuel jets and lair supply tube whenin the position shown in Figure l no float chamber will be needed thusconducing to simplicity and cheapness of con-` struction and eliminatingany float feed which is often a source of trouble.

ln the form shown in Figure l the fluid Y of the piston round the jettube is obtained by means of a split bush z' surrounding the jet tubeand arranged within the cylinder, such split bush having its parts 'heldtogether by means of springs 7c which also serve to control a. splitsleeve Z round the piston so to press the same tightly against :diewalls of the cylinder and thus maintain iiuid tightness of the pistonwithin its cylinder.

ln an alternative form of fluid-tight connection in accordance with theinvention illustrated in Figure 4 the iet tube is surrounded by a splitbush z" having its ends coiled or bevelled so that the parts may bepressedntogetlier by means of a spring m at one end and a plate itscrewed to the piston at the other end, the outer sleeve Z beingmaintained in fluid-tight contact With the cylinder Wall by means of thesprings k which in this case however need not press upon the inner bush.

l Wle ind that very satisfactory results may be obtained from ourcarburetor when the saine is combined With any suitable air heatingsystem by which the incoming air may be heated either by the exhaust gasfrom the engine or otherwise.

Ne Wish it to be understood that the invention is not to be confined tothe foregoing details of construction which are given purely by Way ofillustration and not of limitation since We may vary the form of our jettube and its locationttvhether vertical, horizontal or inclined) and Wemay also vary the vmeans adopted `'for *maintaining fluidtightconnectionbetween' the jet tube and con-trolling piston surrounding the rsame asalso the means adopted for actuating` the piston Vdepending upon anyparticular practical requirements that may have `to 'be fullilled;

Having nonT described our invention *what We claim as new and desire tosecure by Letters Patent is :--V y l. A carburetor for internalcombustion engines comprising in combination a jet tube through whichthe fuel may issue laterally, an air inlet pipe lacross Awhich said jettube extends, a piston surrounding said jet tube, a cylinder Withinwhich said piston is slidable and an axially split sleeve surroundingsaid piston and making` fluid-tight contact with the Wall of saidcylinder.` I

2. A carburetor for internal combustion engines comprising lincombination a jet tube trom Whichtuel may issue laterally, an air inletpipe yacross which said jet tube extends, a piston oo-axialcxvith saidjet tube, a cylinder Within which said Apiston is slidable,

a split sleeve surrounding said piston7 a splitv bush surrounding saidjet tube and enclosed by said' piston and springs interposed betweensaid split bush and said split sleeve.

In testimony whereof We have signed our names to this specification.

l MATTHEW PURVS.

THOMAS LEE.

